Interpretive Summary: Bate is a product used to digest and remove undesirable proteins from hides being processed into leather. Much of the bate used commercially is derived from meat animal pancreas. The activity of pancreatic bate is due largely to the presence of two protein-digesting enzymes, chymotrypsin and trypsin. Bate is usually added to a suspension of hides in water. For experimental purposes, investigators needed to know whether bate would be active in the presence of concentrated salt. For this purpose they determined its activity in the presence and absence of salt. A synthetic peptide that yields an easily measurable colored product when digested was used as an experimental substrate instead of a protein. To determine enzymatic activity, the product concentration was measured every 30 seconds for 5-10 minutes after the substrate and enzyme (bate) were mixed together. The data collected were analyzed mathematically. The results demonstrated that common salt or ammonium sulfate at a very high concentration increases the proteolytic activity of bate by 60-75 percent. Experiments similar to the above were carried out with the pure enzyme chymotrypsin. From the two sets of experiments we determined that the equivalent chymotrypsin content of pancreatic bate is approximately 0.12%. The results shed new light on the bating process and should assist tanners in achieving the maximum benefit from their use of bate in the leathermaking process.

Technical Abstract:
The proteolytic activity of pancreatic bate was determined in media of low ionic strength and in the presence of sodium chloride or ammonium sulfate at an ionic strength of 4. A peptide yielding p-nitroaniline as the hydrolytic product was used as the substrate. The course of the hydrolysis was monitored by measuring the absorbance due to the product every 30 seconds for 5-10 minutes. Initial velocities were determined by fitting the observations with an equation expressing the product concentration explicitly as a function of time and inserting the parameters thereby determined into the Michaelis-Menten equation. Specific enzymatic activities (SA) were calculated from the dependence of the initial velocity on the enzyme (bate) concentration. The ratio of the SAs in the presence and absence of sodium chloride or ammonium sulfate yielded the desired relative activities. Our results demonstrated that sodium chloride and ammonium sulfate at an ionic strength of 4 increase the proteolytic activity of bate by 60-75 percent. Experiments similar to the above were carried out with chymotrypsin. From the two sets of experiments we determined that the equivalent chymotrypsin content of pancreatic bate is approximately 0.12%.